The importance of understanding enclosed space working

Enclosed space working and entry in the marine environment is still costing too many lives
Enclosed space working and entry in the marine environment is still costing too many lives

Feature article written by Capt Michael Lloyd RD**, MNM, FNI

Enclosed space working and entry and the resulting deaths caused by poor procedures and/or lack of knowledge each year is a vexing subject and one that the International Institute of Marine Surveying has highlighted before. However, it seems insufficient progress is being made in this area and the number of casualties remains stubbornly high. Capt Michael Lloyd has become passionate about the subject of enclosed space working and is now something of an authority in the field. In this article, Michael shares his current thoughts on the matter and offers some practical tips and advice for surveyors.

Accidental death on ships is tragic, wasteful and distressing, especially when following the correct procedures, or having the right equipment could have avoided the death. So much has been said about enclosed space working that it would seem there is nothing left to say. There are many booklets, posters, videos, ISM statements and safety meetings; so why are people still dying regularly?

The initial problem with enclosed space working is in the definition and the difficulty of people to realise that in fact, the entire ship is one huge enclosed space divided up into many separate spaces.

We also have to allow for the changing nature of some of the spaces. In bad weather vents on the forecastle and sometimes the main deck will be covered. In this way spaces that are normally safe and entered without second thought now become hazardous, and more so dependent on what is stored there and how it affects the oxygen in the compartment. There are numerous cases of ships sailing for weeks without opening their hatch access cofferdams. Even the main deck becomes an, ‘enclosed space’ for definition of heavier than air gases that can escape on some types of vessels.

The human being requires an atmosphere of 20.93% Oxygen and 79.04% Nitrogen with the remainder being Carbon di-oxide. Any space that has less that 20.8% oxygen is a potential hazard that could eventually be fatal to any human. Now as we know, most substances give off gases of some kind or other, even the bulkheads of an empty space can do this through rust and paint, therefore any space that has been closed for some time without any ventilation must be considered as a hazard.

Perhaps one day all compartments which have no permanent natural ventilation will be fitted with a gas detection meter that will show the reading from the outside in order that it can be checked before anyone enters, but until then we are presently reliant on a rigid safety assessment system being in place to ensure that this check is made.

The principle must be that all spaces that have been closed for any period of time, especially those with seals such as tanks, stores with weather or storm doors are potentially dangerous.

The most difficult spaces are the double bottom tanks. These are similar to a coalmine with the added difficulty of an obstacle course. They are unlit, often mud covered,, honeycombed with steel subdivisions that separate the tanks into small separate compartments with often only four to five feet head room, barely enough space to turn around and each one entered through holes of around 18 inches in diameter. On larger vessels these spaces can span hundreds of feet.

Also in such tanks the problem of rust which depletes the oxygen exists. Not just large ships either. One 500 dwt ship took 5 tons of rust out of two after ballast tanks while engaged in cleaning the tanks.


Proper equipment for enclosed space working, entry and rescue from these spaces is essential.

Obviously, before entering such a space, the normal precautions should have been taken. The tank will have been ventilated for at least 24 hours, and all the checks will have been made with a gas detector which will check for oxygen levels and gases. Unbelievably, it is only last year that these became mandatory.

The problem with this is the oxygen testing is done at the entrance. What is the state of the air in the centre? Let us say that before the surveyor boards, the crew make their test reading and it shows a safe atmosphere at the entrance point. As far as they are concerned, that space is safe to enter, which doesn’t do the surveyor much good when he collapses half way through the space.


Consider that any entrants or rescuers will have to go through lightning holes often less than half a metre diameter. The only SCBA sets most ships carry are designed for fighting fires. There are SCBA sets designed for such tight spaces but there is no SOLAS requirement to carry them and very few ships have these. This makes the procedure on many ships involve trying to put the BA set on when in the space while hanging onto a ladder. Imagine the time it is going to take with such equipment. That is of course assuming that the ship has a properly trained rescue team which the vast majority does not.


The stretchers we have are often not designed for such spaces and require four persons to carry them, indeed the design of many of these goes back a hundred years. Yet ashore there are stretchers used by rescue organisations that can be used in such spaces, that can be manoeuvred through small holes and only require two persons to carry them. Not required.

Standard ships Breathing Apparatus

If the space is not easily accessible, such as a deep tank or a double bottom, there are a number of problems to deal with. If there are manholes or lightening holes to go through, then as well as ensuring that the casualty has a constant air supply, it will require a minimum of two strong persons in BA sets to get an unconscious person through these. The difficulty could be increased by the necessity of having to remove the BA sets in order to pass through the holes.  Increased exertion will require the tanks to be supplying full air and this will be using up the air available very quickly therefore spare tanks will have to be kept ready. Alternatively airlines can be used instead of BA sets but this has the risk of entanglement if various obstacles have to be negotiated. The chances are that by the time such a rescue attempt reaches the casualty, it will be too late.

Compressed Air Breathing Lines

In spaces where it is not possible to enter using the standard SCBA sets, there are only two alternatives and that is to use a SCBA set with small cylinders, which will limit the rescue time available, or to use on outside cylinders with breathing lines attached.

The supply of air can either be by a dedicated on board airline, a compressor or from cylinders on a transportation trolley. One advantage is that a number of rescuers can use the same system. Provided there is enough air supplied. Again, however the time element comes in to play.


This would then indicate that the best method or rescue is to treat the casualty immediately the rescue party reaches him. This requires a resuscitator. It is portable and small enough to be placed onto a casualty’s chest on a stretcher to ensure a constant supply of air throughout the rescue. But how many ships have one? There is no legislation from the IMO requiring this essential equipment.


For a vertical access point, these are essential in retrieving a casualty yet again not many ships have one or have training in their use. All too often ships are reliant on an improvised cargo residue hoist rather than a dedicated rescue device. On a very recent casualty involving a well-known British company, all they had was a length of rope. No training, no rescue equipment, and no hope for the two casualties. I suggest no safety culture in the office ashore either.

Tripods have self-supporting anchors and often if there is insufficient space above an entry point, the winch arrangement can be disconnected from the tripod and an eye bolt or a strop above the entry point can be used. Quadpods are stronger and more versatile than tripods. The fourth leg allows them to straddle manholes and also gives them more stability on a rolling deck. A typical one is light with aluminium legs and a SWL of around 300Kg. Again, in standard use ashore in industry.


Finally and most important, on the majority of dry cargo ships, those entering the tanks have to rely on crew who have had no formal training to rescue them and those directing the attempt also having had no formal training in enclosed space rescue management. There are many courses available and in occupations ashore where personnel are working regularly with such spaces, training in entry, rescue management and rescue is mandatory. No reputable land based company would consider anyone entertaining enclosed space working in such spaces without this training being in place.

Specific Training

Although required in many industries ashore, formal training in enclosed space working, entry and rescue is as yet not required for seamen on ships other than tankers and chemical carriers. Yet the Marine Accident Investigators’ International Forum have found that over 75% of deaths in these spaces occurred on ships that were not tankers or chemical carriers.

In their findings, which will not come as any surprise to those at sea, they list amongst the areas of concern;
1. Lack of knowledge, training and understanding of the dangers of entering enclosed spaces.
2. Personal protective Equipment or rescue equipment not being used, not available of appropriate type, improperly used, or in disrepair.

This means that any ability and knowledge for this has to be taught on board often by those with no experience either.

The Management of Enclosed Spaces

At sea, this is not yet seen as a problem that assists with the prevention of accidents in these spaces yet as has been shown, in many cases, it is the lack of knowledge of a space that has contributed towards an accident and hindered the rescue attempt.

As many surveyors will know, each space on a ship can present different problems. Ladders may have rungs missing. One entry point may be difficult and another easier. Walkways may be unguarded in one space but guarded in another. Ventilation and lighting differ. There are so many variables yet too often we find that a risk assessment is made to cover all spaces and no detail of individual spaces and their problems recorded.

This meant that when entry was required, especially by those unfamiliar with a space, there was no information that could be given prior to entry to enable that person to understand what particular problem would be encountered.

Based on MRSL’s experiences on many ships and rigs, a computerised management system has been designed to enable all such information to be recorded on each space and better still to allow such information to accumulate over time and not leave the ship with each change of personnel.

Better still the required documentation for entry such as work permits can be printed out together with a report of any particular space and forwarded ahead of the ships arrival at a port where the space will be entered. This enables those about to enter have a preliminary report on the space and any pertinent information. If there is any perceived problem it at least allows this to be discussed with the ship managers prior to the ships arrival and, if necessary either rectified or precautions such as a standby rescue team or specialist equipment be supplied.

There is however a motto beloved of ship owners and managers. ‘If it is not legally required, then don’t supply it.’

The answers, as always, are in equipment and training. Safety conscious companies will do what they can but it is always the same few companies that do this while many do not. If a ship does not have the correct equipment and there is a serious doubt that a rescue can be affected from a space that crew are entering, then if a full check of the entire space cannot be carried out properly, it must be questioned as to why persons are willing to enter that space, regardless of the seemingly urgency of the task.

Those most at risk are the shore personnel, such as surveyors, who attend a vessel for a few hours, with no knowledge of that specific ship and the spaces, and have to enter spaces and are reliant on the crew to respond aptly and promptly in an emergency.

I remember a time in my career when I was trading regularly to the Gulf and being appointed ashore there for some time. During this period I was asked to do surveys on behalf of a classification society and boarding a number of ships, had a chance to see the other side of the coin. In some cases, when I had to survey a tank, they could not even find the correct entry point never mind prepare the tank for inspection. On one ship I walked off and refused to carry on. When the class surveyor tried to urge me to go back, I suggested that he do the survey instead.

It is our experience in MRSL that there are very few ships that have adequate rescue equipment or the training in rescue. If this is the case, it makes it essential that those entering these spaces, especially surveyors who are completely reliant on the safety regime of the ship, take every precaution they can before entering.

A brief checklist would be as follows:

The Surveyor
PPE equipment
– Safety helmet with lighting and comms
– Gas detector
– Safety Harness
– Emergency Escape Breathing Apparatus

The Ship
– Tripod or winch arrangement for recovery
– Resuscitator
– Two BA sets suitable for entry at the entry point
– Stretcher suitable for space being entered
– Guardian at the entry point
– One responsible crew member to accompany the person entering
– Rescue party of at least two persons capable of entry and carrying a stretcher

Viewed Documentation
– Risk assessment of the space
– Work Permit
– Record of ventilation
– Record of gas testing of the space

A surveyor may consider this excessive. If this is so, then he can decide what he requires, is it his life? However, I would point out that if I were the Captain, I would insist that this be followed.

As all of us concerned with ships know, the standard of professionalism and seamanship is in decline, and the manning is minimal. These factors may lead such precautions to be declined, especially as the manpower requirement could well take all the deck crew away from any other work. That is not the surveyors concern, going off the ship safely is, and that of course is his option.

The more those visiting a ship from ashore require that the safe and proper precautions that they would expect ashore are taken on board, then the more the ship owners and managers will be required to treat the possible dangers of these spaces with the seriousness they deserve. As they find that the delays incurred by surveyors refusing to enter a space or the cost of hiring standby rescue teams and equipment from ashore accumulate, they will realise that it is better to train and have the correct equipment and procedures on board.

It is surely ridiculous that what is considered to be normal precautions to take ashore in industry is considered not to be required on ships. The sooner we all work together on the problem of enclosed space working and entry, both for those ashore and those at sea, the sooner we will solve this last vestige of safety hazard deniability in the shipping companies and in the IMO, where the real responsibility lies for the failures to stop the unnecessary deaths that are occurring with such frequency in these spaces.

MRSL run specialist courses in enclosed space working and entry.

Instagram Posts from the IIMS @iimsmarine